New old stock used to refer to old inventory that a store had that had never sold. Sat on a back shelf somewhere, kind of dusty, a bit older, maybe a little scuffed by all the stuff sitting next to it, but still in good shape. That's what people pay extra for. Now NOS has been inflated to include pretty much whatever a seller wants it to mean. Sometimes even sellers with good reputations. Which is why I rarely buy things listed as NOS anymore. But I do remember when it had a meaning that had some value to it.